An easy way to test your idea is to cut faux panels out of brown paper and mount them on your walls with small amounts of masking tape. Strips of plain or colored masking tape can stand in for the wood trim that will define your panels. Use your carpenter's level or t-square to check that panels are level and in line with walls. Test your ideas on one or more walls so you're certain that the overall effect is not overwhelming. Making your panel design smaller or simpler is easy with paper patterns, but difficult when you are ordering and cutting wood trim. Once your paper design achieves your goal, measure the patterns to determine the materials you need. Taking extra time to make certain your measurements are precise is the most important key to successful faux paneling.
Visit more than one home improvement center or lumber yard if possible, so that you have the best choice of molding styles. Online catalogs can help define your ideas, but you will want to examine molding and ask questions in person. The supplies you will need include the molding, a mitre box or board for cutting angles, a carpenter's level or square, a small wood saw (a coping saw is adequate), white glue, finishing nails and a hammer (or a nail gun).
Sometimes the subtle look of trim painted the same color as the wall is just the right touch. Other possibilities include contrasting trim with wall color and/or filling the faux panels with wallpaper, other textured paper or even thin sheet cork. Pairing white trim with a soft wall color gives a crisp definition to the walls. Framing wallpaper, textured paper or cork with a trim that contrasts with the walls has a stronger effect. For example, off-white walls take on an exhuberant punch when a dark green trim accentuates one of the colors in the floral wallpaper faux panel center. Let a texture define panels painted the same color as the walls.
Most often frame is glued and nailed in place first and the centers of panels are cut and fitted once the glue is dry. Experiment, if you like, with applying centers to the wall first, framing them with trim. In either case, measure trim one panel at a time and cut mitred edges so that corners will fit smoothly. If you have not used a mitre box before, practice cutting on an extra piece of trim so that your cuts will be smooth.
Coat the backs of your trim pieces with white glue and allow it to rest for five minutes until it becomes slightly tacky. Press it to the wall and wipe off any excess glue. Press the trim piece firmly to the wall and anchor with finishing nails close to both ends. Minor finishing chores include spackling over nail heads and dabbing paint over the spackling. Although this seems like a number of steps, even beginning do-it-yourselfers will find the skills needed to do this handsome project well within their abilities.